OFF THE COAST OF BAHRAIN — As President Trump and Iran trade threats, ships such as the USS Whirlwind are at the front lines of the rising frictions, patrolling the strategic waterways of the Persian Gulf.

Here, American Navy vessels come close to Iranian ships on a daily basis.

“If we see them and they hail us, we’ll just tell them we are a coalition warship. It’s just normal professional dialogue,” said Lt. Cmdr. Yilei Liu, the ship’s commanding officer. “Everybody is just trying to understand what everybody else is doing.”

A 178-foot patrol boat, the Whirlwind is one of 21 forward-deployed ships with the U.S. 5th Fleet in Manama, Bahrain, which carry out surveillance and operations such as boarding and searching suspicious vessels. The stated aim of the mission is to ensure freedom of navigation and commerce in one of the world’s most vital waterways.

Last month, when limpet mines blasted two petrochemical tankers in the Gulf of Oman, forcing both crews to abandon ship as thick plumes of black smoke rose into the air, the U.S. Navy responded to the distress calls. Those incidents came after Emirati authorities said four ships had been sabotaged in the United Arab Emirates port of Fujairah.

The United States has blamed Iran for the attacks. Iran denies carrying them out.

They came against a backdrop of increasing friction between Tehran and Washington after the Trump administration last year withdrew from the landmark nuclear deal and reimposed economic sanctions on Iran. On Monday, Iran exceeded the limit on uranium enrichment set by the 2015 accord that Tehran negotiated with the United States and other world powers, according to a spokesman for Iran’s Atomic Energy Organization.

The Pentagon dispatched about 2,500 additional troops to the Persian Gulf region last month, citing information that Iran was planning to harm U.S. interests. The show of force included the deployment of an aircraft carrier and amphibious assault ship. 

Of all its military assets, the Navy is the United States’ most visible deterrent.

Liu would not go into the details of additional force protection put in place in recent months. “We’re basically ready to respond to any kind of regional adversary action,” said Liu, of San Diego, whose command of the Whirlwind is his first after 13 years in the Navy. “We are trained to defend the ship, we are trained to fight and ready to fight. We are postured to take action if necessary in the region against any threats in the region.” 

Despite the drama of the past few months, for the sailors patrolling the waterway, it’s been business as usual.

On a searing hot day last week, the Whirlwind cast off from port in Manama to carry out a joint exercise with its sister ship, the USS Hurricane. 

The Whirlwind clipped along at a speed of 32 knots, passing traditional wooden dhows and oil tankers. One-fifth of the world’s oil passes through the Strait of Hormuz, where shipping lanes narrow to just a few miles across. 

A large part of the patrol boat’s mission is surveillance, Liu said. “We look at what people are doing, patterns of life.” 

The Whirlwind is one of the smallest vessels in the U.S. Navy, and it’s all hands on deck for the four officers and 26 enlisted sailors on board. For example, culinary specialist Jonathan Osuna, who ducks below deck to cook spaghetti and meatballs to the sounds of Frank Sinatra, also drives the ship into port. 

“Because we are so small, pretty much everybody does everything,” said Lt. Erik Anastos, operations officer, who is from Arlington, Va.

After the raising of a huge American flag, the crew is ordered to be “ready for adversary action,” manning the weapons stations that include four mounted machine guns and a Griffin missile system. They haul on their helmets and body armor. 

“When we man gun quarters, the whole crew is involved in some fashion,” said Lt. Austin Nodolf, weapons officer. “The people who handle the lines, the IT men, basically every kind of rig operates the gun mounts.” 

At the back of the ship is a boat deck with a seven-meter rib, which can slide into the water so the crew can board other ships. But the only time it’s been used in recent months was in a goodwill mission in cooperation with the Qatari navy. The crew coordinates closely with allied navies in the region, including those of Bahrain, Iraq, Saudi Arabia and the UAE.

The ship will spend a maximum of about 10 days on patrol out of port at a time. In between, the crew carries out routine exercises. 

The temperature in Manama has been hovering around 110 degrees. But on the deck of the four-engine ship, the thermometer hits 120 degrees. So while there has been a growing prospect of hostilities with Iran, the most immediate challenge is the heat, according to hospital corpsman Jose Gonzalez of Texas, who is tasked with handling anything medical-related onboard. 

“We are doing the same thing we always do,” said Gonzalez. “Nothing’s changed.”